1. Field of the Invention
The present invention relates to an evaporation valve pipe fastening structure for preventing a pipe connecting evaporation valves from coming away from the valves.
2. Description of the Related Art
Conventionally, evaporation valves have been employed to prevent vapor within a fuel tank being discharged to outside and to prevent fuel within the fuel tank from flowing to outside. There has, however, been a tendency to provide such evaporation valves within fuel tanks, to take into consideration safety aspects at the time of vehicle collisions and to make the overall structure smaller. When a plurality of evaporation valves are provided within a related fuel tank, each evaporation valve is fixed to the inner wall of the fuel tank using a bracket and pipes connecting the evaporation valves are attached right next to the evaporation valves. There is therefore almost no fear of the pipes coming away and no problem regarding the force required to pull the pipes away.
However, recently, upper surfaces of fuel tanks have become complex in shape and there are therefore cases where connecting pipes cannot be connected directly next to the evaporation valves. There are also cases where connecting pipes are vertically attached at a lower side of a two-way valve when evaporation valves are connected to such valves. There are therefore cases where pipes may come away in a downward direction with the related art where pipes are attached transversely. It is therefore necessary to fix such pipes to the fuel tank using a supporting bracket when there is a possibility that a pipe may come away from the fuel tank in a downward direction.
As the present invention sets out to resolve the aforementioned points, it is the object of the present invention to provide a pipe fastening structure where a pipe is resistant to a large pulling force and will not come away even when it is attached at the lower side of an evaporation valve in a direction pointing straight downwards.
In order to achieve the aforementioned object, in the present invention, a pipe-fastening structure for an evaporation valve having a housing and a gas extraction path formed within the housing comprises a cylindrical connecting member, a stopper member, a variable member, channels, a pipe, and a large diameter bulge section. The cylindrical connecting member is fixed to the housing and has first engaging means formed at an outer wall and an inner space communicating with the gas extraction path. The stopper member has a cylindrical inner member and second engaging means engaging with the first engaging means in two stages, closely fitting with the inner and outer walls of the cylindrical connecting member. The variable member is formed at part of the inner member in a cylindrical shape with a diameter capable of enlargement. The channels are formed in the same circumferential direction at the inner wall of the variable member at a position midway in the axial direction. The pipe is for connecting evaporation valves. The large diameter bulge section is formed in the vicinity of an end of the pipe. Locations of the inner member other than the variable member fit closely with the cylindrical inner wall of the connecting member and the first and second engaging means undergo first stage engagement. The pipe and the stopper member are then moved with respect to the connecting member, the variable member fits closely with the inner wall of the connecting member, and the first and second engaging means undergo second stage engagement.
The connecting member can be fixed to the housing using fixing means formed separately from the housing, or can be formed integrally with the housing.
The variable member can comprise a multiplicity of arms and slits formed between the arms.
In the present invention, when the first and second engaging means undergo the first stage engagement and the second stage engagement, engagement is not released even if the stopper member is subjected to external force in a direction opposite to a direction of attachment of the stopper member.
The first engaging means can also comprise of a first raised portion, a first recess, a second raised portion and a second recess, formed in that order in the axial direction at the outer wall of the connecting member, and the second engaging means can be an engaging claw.
According to the evaporation valve pipe fastening structure of the present invention, a housing, connecting member in a fixed state, and a pipe are attached via a stopper member. The stopper member is provided in such a manner that it is not possible to pull the stopper member away from the connecting member, and it is ensured that the pipe cannot be drawn away from the evaporation valve by ensuring that the pipe attached to the stopper member cannot be pulled away from the stopper member. As a result, the pipe will not come away from the evaporation valve even if the pipe is attached at a position directly below the evaporation valve.
The pipe can therefore also be arranged directly below the evaporation valve in an economic manner because the use of a supporting bracket to support the pipe is no longer necessary as there is no fear of the pipe coming away from the evaporation valve.